SAAD = Spooky action at a distance Is faster-than-light communication possible?
Let's think about what happens when a photon passes both the slits and hit (or doesn't hit) the screen. It is said that the photon travels all possible paths (hence the wave) and collapses to a point. In another word, the photon interferes with itself.
Let's take a look at the picture. After passing the double slits, part of the photon follows the path L1 and part of the photon follows the path L2. There is a difference between L1 and L2 and in the double slits experiment, the difference should be a few lambdas (of the photon). If the photon collapse at that point, it probably implies part of the photon travels faster than the other part. And if the path difference is significant, we may expect to see faster-than-light interactions.
In the setup above, can a photon interfere with itself? We can limit the path difference to a few lambdas so this setup will have the silmilar result as the double-slit. But when we enlarge this difference, what will happen? If the self-interference disappears, then what is the maximum path difference and why? If there is no maximum path difference for this self-interference, then there will be a very interesting effect.
